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Finding the Fourth Proportional to 102.50, 141.45 and 80.78

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Solution

The fourth proportional to 102.50, 141.45 and 80.78 is: 111.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.50 : 141.45 = 80.78 : x
  2. Step 2: Convert to fraction form
    102.50/141.45 = 80.78/x
  3. Step 3: Cross multiply
    102.50x = 141.45 × 80.78
  4. Step 4: Simplify right side
    102.50x = 11,426.33
  5. Step 5: Solve for x
    x = 11,426.33/102.50
  6. Step 6: Final answer
    x = 111.48

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.